Flat-panel display devices such as those having liquid crystal panels or organic electroluminescent (EL) panels have been used in various fields. Recently, flexible display devices capable of being bent have been developed by using flexible substrates formed of flexible materials as boards for display devices.
In general, a display device includes a display area where an image is displayed, and a frame area located around the display region and connected to drive circuits and external circuits.
This display device is strongly required to make a frame area narrower (i.e., to narrow a frame) to further increase the display area from the viewpoint of performance, design, and the like. To narrow the frame of the flexible display device, the frame area of the flexible display device is bent, and the frame area outside the bent area is arranged on a back surface side of the flexible display device, thereby effectively enlarging the display area.
In the prior art display device, an inorganic electrically insulating film is sometimes disposed on the entire surface of the flexible substrate in order to prevent moisture from entering therein. The inorganic insulating film generally has a higher resistance to bending stress as compared to the flexible substrate. Therefore, in the case where the inorganic insulating film is present on the area to be bent in the display device, bending stress is applied to the inorganic insulating film when the display device is bent, which may lead to cracking of the inorganic insulating film. With the cracking of the inorganic insulating film, the wiring disposed on the inorganic insulating film may be broken.